Symptom cluster research is an emerging area in the field of oncology symptom management. While an increase in knowledge about symptom clusters has occurred in the past seven years, a number of outstanding issues and questions remain. The overall goal of this grant application is to further our understanding of the occurrence and effects of symptom clusters in oncology patients. Specifically, this study will address two important aspects of symptom cluster research, namely 1) the identification of symptom clusters in oncology outpatients who are receiving chemotherapy (CTX) AND 2) the identification of subgroups of oncology outpatients based on their experience with four highly prevalent symptoms (i.e., pain, fatigue, sleep disturbance, and depression). Based on five preliminary studies, we will attempt to identify the genomic markers for the different patient subgroups identified in part 2 of this study. Patients (n=1786 to have a final sample of 1500) with breast, lung, colon, and ovarian cancer who will receive their second or third cycle of CTX will be enrolled in this longitudinal study. Patients will complete self-report questionnaires a total of six times over 2 cycles of CTX to evaluate for the number and types of symptom clusters and for changes in symptom clusters over time. In addition, cluster analysis procedures will be employed to create subgroups of patients based on their experience with the symptoms of pain, fatigue, sleep disturbance and depression. Based on our previous research we anticipate that two subgroups of patients will be identified (i.e., patients who experience high level of all four symptoms (~10. percent of the sample) and patients who experience low levels of all four symptoms (4.3 percent of the sample). A two stage genome wide association study will be done with the DNA from these two subgroups to identify genomic markers for these two distinct groups of patients.